<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Bootstrap</title>
    <link rel="stylesheet" type="text/css" href="./css/bootstrap.min.css">
</head>
<body>
    <div class="container">
        <div class="jumbotron">
            <h1>Hello, world!</h1>
        </div>
        <div class="row">
            <div class="col-lg-3 col-lg-push-9 col-md-4 col-md-push-8 col-sm-6 col-sm-push-6">
                <div class="thumbnail">
                    <img src="./img/Bootstrap.png">
                    <class class="caption text-center">
                        <h3>优站精选</h3>
                        <p><a href="javascript:;">Bootstrap 网站实例</a></p>
                        <p>Bootstrap 优站精选频道收集了众多基于 Bootstrap 构建、设计精美的、有创意的网站。</p>
                    </class>
                </div>
            </div>
            <!-- 必须加上col-md-pull-0，不能跳着写 -->
            <div class="col-lg-3 col-lg-push-3 col-md-4 col-md-pull-0 col-sm-6 col-sm-pull-6">
                <div class="thumbnail">
                    <img src="./img/react.png">
                    <class class="caption text-center">
                        <h3>优站精选</h3>
                        <p><a href="javascript:;">Bootstrap 网站实例</a></p>
                        <p>Bootstrap 优站精选频道收集了众多基于 Bootstrap 构建、设计精美的、有创意的网站。</p>
                    </class>
                </div>
            </div>
            <div class="col-lg-3 col-lg-pull-3 col-md-4 col-md-pull-8 col-sm-6">
                <div class="thumbnail">
                    <img src="./img/webpack.png">
                    <class class="caption text-center">
                        <h3>优站精选</h3>
                        <p><a href="javascript:;">Bootstrap 网站实例</a></p>
                        <p>Bootstrap 优站精选频道收集了众多基于 Bootstrap 构建、设计精美的、有创意的网站。</p>
                    </class>
                </div>
            </div>
            <div class="col-lg-3 col-lg-pull-9 col-md-4 col-sm-6">
                <div class="thumbnail">
                    <img src="./img/typescript.png">
                    <class class="caption text-center">
                        <h3>优站精选</h3>
                        <p><a href="javascript:;">Bootstrap 网站实例</a></p>
                        <p>Bootstrap 优站精选频道收集了众多基于 Bootstrap 构建、设计精美的、有创意的网站。</p>
                    </class>
                </div>
            </div>
        </div>
    </div>
</body>
<script type="text/javascript" src="./js/bootstrap.min.js"></script>
<script type="text/javascript" src="./js/jquery-3.5.1.min.js"></script>
</html>